Food handling gripper

ABSTRACT

Exemplary embodiments relate to improvements in robotic systems to reduce biological or chemical harborage points on the systems. For example, in exemplary embodiments, robotic actuators, hubs, or entire robotic systems may be configured to allow crevices along joints or near fasteners to be reduced or eliminated, hard corners to be replaced with rounded edges, certain components or harborage points to be eliminated, shapes to be reconfigured to be smoother or flat, and/or or surfaces to be reconfigurable for simpler cleaning.

RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.16/148,170 filed on Oct. 1, 2018, which is a Continuation of U.S.application Ser. No. 15/194,283 filed on Jun. 27, 2016, now U.S. Pat.No. 10,112, 310, issued on Oct. 30, 2018, which claims priority to U.S.Provisional Patent Application Ser. No. 62/185,385, filed on Jun. 26,2015 and entitled “Food Handling Gripper.” The contents of theaforementioned applications are incorporated herein by reference.

BACKGROUND

Robotic systems are employed in a number of different contexts, and maybe called upon to perform a wide variety of different tasks. Robotstypically manipulate objects around them using robotic manipulators suchas individual actuators, grippers, or end effectors.

Soft robotic actuators have recently been employed in contexts in whichtraditional hard actuators may be inappropriate or may suffer fromdeficiencies. For example, in food handling, it may be advantageous touse soft robotic actuators because of their improved ability to conformto the article being grasped, thus preventing the food from becomingmarred or bruised. For similar reasons, soft actuators may be used inmedical settings.

Whether a hard robotic actuator or a soft robotic actuator is employed,the handling of certain biological or chemical materials may pose uniqueproblems. Hard and soft robotic systems may include numerous crevices,surface roughness, indentations, fasteners, and other areas where thebiological or chemical materials may accumulate and breed bacteria orspread potentially poisonous matter to other products. Traditionally, itmay be difficult to remove accumulated biological or chemical materials,thus creating a contamination hazard.

SUMMARY

The present application addresses improvements in robotic systems toreduce biological or chemical harborage points on the systems. Exemplaryembodiments relate to improvements in robotic actuators, grippers, hubsfor connecting the actuators or grippers to a robotic arm, entirerobotic systems, and other components. According to exemplaryembodiments, fasteners and mounting points may be moved to internallocations on actuators and hubs, so as to present a smooth, flat surfacewithout corners, crevices, or other points for biological or chemicalmaterials to accumulate. Attachment points may be configured to usetwist-interlock systems having rounded interlocking pieces that areeasier to clean than sharp corners. Distances between adjacentcomponents (e.g., accordion extensions on actuators) may be increased,and curves added or increased in size, to reduce harborage points.Similarly, specially-configured coverings may be employed to present aflat surface on which biological or chemical materials will exhibitreduced accumulation or which may be readily cleaned; in someembodiments, the coverings may be disposable.

Moreover, some embodiments provide actuators having improved designs forhandling food, biological materials such as tissue, and other delicateor easily bruised or deformed materials.

Although exemplary embodiments are described in connection with softrobotic actuators, similar techniques may be employed with moretraditional hard robotic systems.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1D depict exemplary soft robotic actuators suitable for usewith exemplary embodiments described herein.

FIGS. 2A-2E depict examples of internal attachment mechanisms foraffixing an actuator to a hub according to an exemplary embodiment.

FIGS. 3A-3E depict examples of hub and base assemblies for affixing arobotic gripper to a robotic arm.

FIGS. 4A-4D depict an example of a hub having an internal fixturingmechanism according to exemplary embodiments.

FIGS. 5A-5H depict an example of a twist-lock inflation fluid supplyline, according to an exemplary embodiment.

FIG. 6 depicts a magnetic attachment for an inflation fluid supply line,according to an exemplary embodiment.

FIGS. 7A-7B depict an example of an actuator having reduced harboragepoints, according to an exemplary embodiment.

FIGS. 8A-8C depict an accordion cover for a soft actuator, according toan exemplary embodiment.

FIG. 9 depicts an example of an overmolded soft gripping pad, accordingto an exemplary embodiment.

FIGS. 10A-10C depict examples of inflatable texturing surfaces,according to exemplary embodiments.

FIGS. 11A-11D depict an exemplary tapered soft actuator.

FIGS. 12A-12D depict an exemplary spherically enveloping gripper.

FIGS. 13A-13B depict exemplary webbing applied between actuators.

FIGS. 14A-14B depict exemplary extend-and-grasp actuators.

FIG. 15A-15D depict an actuator incorporating a hook, according to anexemplary embodiment.

FIGS. 16A-16B depict examples of different degrees of vacuum applied toan actuator to modify the actuator's opening profile.

FIGS. 17-17C depict an exemplary disposable wrapping for a roboticsystem.

DETAILED DESCRIPTION

Exemplary embodiments relate to robotic systems that are designed orconfigured to reduce biological or chemical harborage points on thesystems. For example, in exemplary embodiments, robotic actuators, hubs,or entire robotic systems may be configured to allow crevices alongjoints or near fasteners to be reduced or eliminated, hard corners to bereplaced with rounded edges, certain components or harborage points tobe eliminated, shapes to be reconfigured to be smoother or flat, and/oror surfaces to be reconfigurable for simpler cleaning. Improved actuatordesigns for handling certain types of biological or chemical materialsare also disclosed.

Exemplary embodiments may be advantageously employed in conjunction withsoft robotic actuators. Soft robotic actuators are relatively non-rigidactuators that may be actuated by, for example, by filling the actuatorwith a fluid such as air or water. The soft actuator may be configuredso that, by varying the pressure of the fluid in the actuator, the shapeof the actuator changes. Accordingly, the actuator can be made to, forinstance, wrap around an object. Because the soft actuator is relativelynon-rigid, the actuator may better conform to the surface of the graspedobject, allowing the actuator to gain a better hold on the object ormore gently hold fragile objects.

A brief overview of soft robotic actuators and grippers will first beprovided, followed by a detailed description of various aspects ofexemplary embodiments. Unless otherwise noted, it is contemplated thateach of the described embodiments may be used in any combination witheach other.

Background on Soft Robotic Grippers

Conventional robotic grippers or actuators may be expensive andincapable of operating in certain environments where the uncertainty andvariety in the weight, size and shape of the object being handled hasprevented automated solutions from working in the past. The presentapplication describes applications of novel soft robotic actuators thatare adaptive, inexpensive, lightweight, customizable, and simple to use.

Soft robotic actuators may be formed of elastomeric materials, such asrubber, or thin walls of plastic arranged in an accordion structure thatis configured to unfold, stretch, twist and/or bend under pressure, orother suitable relatively soft materials. They may be created, forexample, by molding one or more pieces of the elastomeric material intoa desired shape. Soft robotic actuators may include a hollow interiorthat can be filled with a fluid, such as air, water, or saline topressurize, inflate, and/or actuate the actuator. Upon actuation, theshape or profile of the actuator changes. In the case of anaccordion-style actuator (described in more detail below), actuation maycause the actuator to curve or straighten into a predetermined targetshape. One or more intermediate target shapes between a fully unactuatedshape and a fully actuated shape may be achieved by partially inflatingthe actuator. Alternatively or in addition, the actuator may be actuatedusing a vacuum to remove inflation fluid from the actuator and therebychange the degree to which the actuator bends, twists, and/or extends.

Actuation may also allow the actuator to exert a force on an object,such as an object being grasped or pushed. However, unlike traditionalhard robotic actuators, soft actuators maintain adaptive properties whenactuated such that the soft actuator can partially or fully conform tothe shape of the object being grasped. They can also deflect uponcollision with an object, which may be particularly relevant whenpicking an object off of a pile or out of a bin, since the actuator islikely to collide with neighboring objects in the pile that are not thegrasp target, or the sides of the bin. Furthermore, the amount of forceapplied can be spread out over a larger surface area in a controlledmanner because the material can easily deform. In this way, soft roboticactuators can grip objects without damaging them.

Moreover, soft robotic actuators allow for types of motions orcombinations of motions (including bending, twisting, extending, andcontracting) that can be difficult to achieve with traditional hardrobotic actuators.

FIGS. 1A-1D depict exemplary soft robotic actuators. More specifically,FIG. 1A depicts a side view of a portion of a soft robotic actuator.FIG. 1B depicts the portion from FIG. 1A from the top. FIG. 1C depicts aside view of a portion of the soft robotic actuator including a pumpthat may be manipulated by a user. FIG. 1D depicts an alternativeembodiment for the portion depicted in FIG. 1C.

An actuator may be a soft robotic actuator 100, as depicted in FIG. 1A,which is inflatable with an inflation fluid such as air, water, orsaline. The inflation fluid may be provided via an inflation device 120through a fluidic connection 118.

The actuator 100 may be in an uninflated state in which a limited amountof inflation fluid is present in the actuator 100 at substantially thesame pressure as the ambient environment. The actuator 100 may also bein a fully inflated state in which a predetermined amount of inflationfluid is present in the actuator 100 (the predetermined amountcorresponding to a predetermined maximum force to be applied by theactuator 100 or a predetermined maximum pressure applied by theinflation fluid on the actuator 100). The actuator 100 may also be in afull vacuum state, in which all fluid is removed from the actuator 100,or a partial vacuum state, in which some fluid is present in theactuator 100 but at a pressure that is less than the ambient pressure.Furthermore, the actuator 100 may be in a partially inflated state inwhich the actuator 100 contains less than the predetermined amount ofinflation fluid that is present in the fully inflated state, but morethan no (or very limited) inflation fluid.

In the inflated state, the actuator 100 may exhibit a tendency to curvearound a central axis as shown in FIG. 1A. For ease of discussion,several directions are defined herein. An axial direction passes throughthe central axis around which the actuator 100 curves, as shown in FIG.1B. A radial direction extends in a direction perpendicular to the axialdirection, in the direction of the radius of the partial circle formedby the inflated actuator 100. A circumferential direction extends alonga circumference of the inflated actuator 100.

In the inflated state, the actuator 100 may exert a force in the radialdirection along the inner circumferential edge of the actuator 100. Forexample, the inner side of the distal tip of the actuator 100 exerts aforce inward, toward the central axis, which may be leveraged to allowthe actuator 100 to grasp an object (potentially in conjunction with oneor more additional actuators 100). The soft robotic actuator 100 mayremain relatively conformal when inflated, due to the materials used andthe general construction of the actuator 100.

The actuator 100 may be made of one or more elastomeric materials thatallow for a relatively soft or conformal construction. Depending on theapplication, the elastomeric materials may be selected from a group offood-safe, biocompatible, or medically safe, FDA-approved materials. Theelastomeric materials may also be a fluoropolymer elastomer for chemicalresistance. The actuator 100 may be manufactured in a Good ManufacturingProcess (“GMP”)-capable facility.

The actuator 100 may include a base 102 that is substantially flat(although various amendments or appendages may be added to the base 102in order to improve the actuator's gripping and/or bendingcapabilities). The base 102 may form a gripping surface that grasps atarget object.

The actuator 100 may include one or more accordion extensions 104. Theaccordion extensions 104 allow the actuator 100 to bend or flex wheninflated, and help to define the shape of the actuator 100 when in aninflated state. The accordion extensions 104 include a series of ridges106 and troughs 108. The size of the accordion extensions 104 and theplacement of the ridges 106 and troughs 108 can be varied to obtaindifferent shapes or extension profiles.

Although the exemplary actuator of FIGS. 1A-1D is depicted in a “C” oroval shape when deployed, one of ordinary skill in the art willrecognize that the present invention is not so limited. By changing theshape of the body of the actuator 100, or the size, position, orconfiguration of the accordion extensions 104, different sizes, shapes,and configurations may be achieved. Moreover, varying the amount ofinflation fluid provided to the actuator 100 allows the actuator 100 totake on one or more intermediate sizes or shapes between the un-inflatedstate and the inflated state. Thus, an individual actuator 100 can bescalable in size and shape by varying inflation amount, and an actuatorcan be further scalable in size and shape by replacing one actuator 100with another actuator 100 having a different size, shape, orconfiguration.

The actuator 100 extends from a proximal end 112 to a distal end 110.The proximal end 112 connects to an interface 114. The interface 114allows the actuator 100 to be releasably coupled to other parts of arobotic system. The interface 114 may be made of a medically safematerial, such as polyethylene, polypropylene, polycarbonate,polyetheretherketone, acrylonitrile-butadiene-styrene (“ABS”), or acetalhomopolymer. The interface 114 may be releasably coupled to one or bothof the actuator 100 and the flexible tubing 118. The interface 114 mayhave a port for connecting to the actuator 100. Different interfaces 114may have different sizes, numbers, or configurations of actuator ports,in order to accommodate larger or smaller actuators, different numbersof actuators, or actuators in different configurations.

The actuator 100 may be inflated with an inflation fluid supplied froman inflation device 120 through a fluidic connection such as flexibletubing 118. The interface 114 may include or may be attached to a valve116 for allowing fluid to enter the actuator 100 but preventing thefluid from exiting the actuator (unless the valve is opened). Theflexible tubing 118 may also or alternatively attach to an inflatorvalve 124 at the inflation device 120 for regulating the supply ofinflation fluid at the location of the inflation device 120.

The flexible tubing 118 may also include an actuator connectioninterface 122 for releasably connecting to the interface 114 at one endand the inflation device 120 at the other end. By separating the twoparts of the actuator connection interface 122, different inflationdevices 120 may be connected to different interfaces 114 and/oractuators 100.

The inflation fluid may be, for example, air or saline. In the case ofair, the inflation device 120 may include a hand-operated bulb orbellows for supplying ambient air. In the case of saline, the inflationdevice 120 may include a syringe or other appropriate fluid deliverysystem. Alternatively or in addition, the inflation device 120 mayinclude a compressor or pump for supplying the inflation fluid.

The inflation device 120 may include a fluid supply 126 for supplying aninflation fluid. For example, the fluid supply 126 may be a reservoirfor storing compressed air, liquefied or compressed carbon dioxide,liquefied or compressed nitrogen or saline, or may be a vent forsupplying ambient air to the flexible tubing 118.

The inflation device 120 further includes a fluid delivery device 128,such as a pump or compressor, for supplying inflation fluid from thefluid supply 126 to the actuator 100 through the flexible tubing 118.The fluid delivery device 128 may be capable of supplying fluid to theactuator 100 or withdrawing the fluid from the actuator 100. The fluiddelivery device 128 may be powered by electricity. To supply theelectricity, the inflation device 120 may include a power supply 130,such as a battery or an interface to an electrical outlet.

The power supply 130 may also supply power to a control device 132. Thecontrol device 132 may allow a user to control the inflation ordeflation of the actuator, e.g. through one or more actuation buttons134 (or alternative devices, such as a switch). The control device 132may include a controller 136 for sending a control signal to the fluiddelivery device 128 to cause the fluid delivery device 128 to supplyinflation fluid to, or withdraw inflation fluid from, the actuator 100.

As used herein, an actuator typically refers to a single componentresembling the actuator 100. When multiple actuators are employedtogether to form a gripping system that grips a target, such a system isgenerally referred to as a gripper (although some grippers may consistof a single actuator that grips a target in isolation).

Hubs and Mounting Points

Actuators or grippers may be mounted to a robotic arm (for example)either directly or through a separate interface such as a hub.Problematically, the connection between various components may includecrevices or corners that accumulate materials and may be difficult toclean.

It is noted that actuators, grippers, and robotic systems may be cleanedin-place or out-of-place. In-place cleaning generally refers to cleaningsome or all of a robotic system while the various parts of the systemare still connected, without disassembly. For example, in-place cleaningmay involve scrubbing an actuator and gripper assembly while theassembly remains mounted to a robotic arm. Out-of-place cleaninggenerally involves disassembling the assembly to clean the partsindividually and/or access internal areas of the parts. Exemplaryembodiments provide hubs and mounting locations having fewer or smallerharborage points (thus collecting less bacterial, biological, orchemical material). Moreover, exemplary embodiments are easier to cleanin-place or disassemble for out-of-place cleaning, as described below.

FIGS. 2A-2E depict examples of internal attachment mechanisms foraffixing an actuator to a hub according to an exemplary embodiment. FIG.2A depicts an internal cross-sectional view of a configuration for anattachment point for an actuator 100 that includes several harboragepoints.

The actuator 100 has a wall 202 made of an elastomeric material thatsurrounds an internal void 204 configured to be filled with an inflationfluid. At the proximal end of the actuator 100, a flared section 206 isplaced flush with a mounting surface 208, which may be (for example) aninterface to a gripper to be mounted on a robotic arm. A collar 210 maybe snapped around the flared section 206 and secured to the mountingsurface 208. For example, the collar 210 may be fixed to the mountingsurface 208 using a fastening mechanism, such as screws or bolts. Aninflation fluid supply path 212 extends through the mounting surface208, the collar 210, and into the void 204 to supply inflation fluid tothe actuator 100.

At various locations in this configuration, harborage points 214 existwhere chemical or biological material may accumulate and encouragebacterial growth. For example, harborage points 214 exist at theinterface between the actuator 100 and the collar 210, where sharpcorners and crevices allow biological or chemical matter to accumulate.Similarly, harborage points 214 exist at the base of the collar 210,where the collar 210 meets the mounting surface 208.

Furthermore, the actuator 100 is configured to bend when inflated,deflated, or subjected to vacuum. As the actuator 100 bends (e.g., tothe left or right in FIG. 2A), a gap forms between the internal face ofthe collar 210 and the external face of the flared section 206 (and anyother portion of the actuator 100 surrounded by the collar 210). Thisgap can quickly become filled with biological or chemical material andmay include a number of harborage points. Moreover, this gap isdifficult to access with cleaning tools while the actuator 100 isaffixed to the mounting surface 208, making in-place cleaning difficultor impossible.

An improved actuator configuration is depicted in FIG. 2B. In thisexemplary embodiment, the actuator 100 is secured to the mountingsurface 208 using a securing mechanism 216. The securing mechanism 216includes a central body 218 and one or more extensions 220 extendingfrom the central body 218. The extensions 220 are positioned above oneor more ledges 222 formed in the wall 202 of the actuator 100, with agap existing to allow a fastening mechanism 224 (e.g., a bolt or screw)to be inserted through the mounting surface 208 and into a correspondinghole in the body 218 of the securing mechanism 216. When the fasteningmechanism 224 is tightened, the extensions 220 are drawn into the ledges222 and compress the elastomeric material, forming a fluid-tight gasketand a circumferential seal with the mounting surface 208 around theproximal end of the actuator 100. Preferably, the extensions 220 extendas far as possible in order to provide increased surface area forforming the gasket.

The securing mechanism 216 may be made of any suitable material, such asplastic or metal.

As can be seen in FIG. 2B, due to the absence of a collar the number ofharborage points is reduced. In some embodiments, the portion of theflared section 206 that contacts the mounting surface 208 extends atsubstantially a 90° angle away from the mounting surface 208. As aresult, the force exerted by the securing mechanism 216 pushes theflared portion 206 downward, which forms a relatively strong seal withthe mounting surface 208 and reduces the area of the gap between theactuator 100 and the mounting surface 208. Thus, harborage points arereduced in the system.

In some cases, if bacteria should accumulate at the interface betweenthe actuator 100 and the mounting surface 208, the actuator 100 may beremoved from the mounting surface 208 by removing the fasteningmechanism 224, and the actuator 100 may be cleaned (e.g., in adishwasher or an autoclave, if made of suitable materials). Because themounting surface is typically flat, it is also relatively easy to clean.

In some embodiments, the securing mechanism 216 may include an inflationfluid passage allowing inflation fluid to pass through the securingmechanism. The inflation fluid passage may pass through the central body218 along with the fastening mechanism 224, or the inflation fluidpassage and the fastening mechanism may be provided on different partsof the securing mechanism 216, as shown in the configuration depicted inFIG. 2C. In this example, the inflation fluid passage 212 extendsthrough the body 218 of the securing mechanism 216. The securingmechanism 216 is provided with holes in the extensions 220 for receivingfastening mechanisms 224. The ledges 222 in this example include a lowerledge situated below the extensions 220 and an upper ledge providedabove the extensions 220.

The fastening mechanisms 224 are inserted through the mounting surface208 and through a hole in the lower ledge. The fastening mechanisms 224then extend through the corresponding hole in the extensions 220. Insome embodiments, the fastening mechanisms 224 terminate in theextensions 220; in others, the fastening mechanisms 224 penetrate theextensions 220 and extend into hardware overmolded into the upper ledge.When the fastening mechanisms are tightened, the lower ledge (and theupper ledge, if the fastening mechanism extends into it) is drawn tightwith the extensions 220, creating a fluid-tight gasket. Inflation fluidis supplied to the void 204 through the inflation fluid supply passage212. FIG. 2D depicts the securing mechanism 216 of this embodiment inmore detail.

The securing mechanism 216 may be separate from the actuator 100, or maybe integral with the actuator 100. For example, the securing mechanism216 may be fabricated and then overmolded into the actuator 100 at thetime of actuator fabrication.

FIG. 2E depicts an exemplary overmolded insert. In this case, theextensions 220 are provided between optional upper and lower ledges 222(if the ledges 222 are not present, the securing mechanism 216 may besecured to the actuator wall 204 using, for example, surfacetreatments). The securing mechanism 216 receives the fasteningmechanisms 224, which pull the securing mechanism 216 towards themounting surface 208. Advantageously, an o-ring 226 may be providedaround the outer bottom edge of the securing mechanism 216. As thesecuring mechanism 216 is pulled tight against the o-ring 226, theo-ring 226 provides a strong seal, reducing the gap between the securingmechanism 216 and the mounting surface 208.

Furthermore, because of the shape of the relatively hard (as compared tothe o-ring 226) securing mechanism 216, the securing mechanism 216provides a hard stop for the fastening mechanism 224. For example, theo-ring 226 may be silicon or an elastomer such as a flouropolymerelastomer, whereas the securing mechanism 216 may be food-safe plastic(e.g., PETE, delrin, polyethelene, or polypropylene) or metal (e.g.,stainless steel with a grade of 303, 304, or 316, or hard anodizedaluminum). Because of the relatively hard or rigid nature of thesecuring mechanism 216, there comes a point during the tightening of thefastening mechanisms 224 when the securing mechanism 216 cannot be drawnfurther towards the mounting surface 208. This prevents the o-ring 226from becoming over- or under-compressed and allows the securingmechanism 216 to be tuned (by varying the shape of the securingmechanism 216, particularly the size and configuration of the gap whichseats the o-ring 226) to put a predetermined amount of force on theo-ring 226.

Traditionally, external screws or bolts are used to fix an actuator oractuator assembly to a mounting surface 208. These external fasteningmechanisms create harborage points; the embodiments of FIGS. 2A-2Eeliminate the external fastening mechanisms and replace them withinternal fastening mechanisms to thereby reduce or eliminate theseharborage points. Moreover, the interface between the actuator 100 andthe mounting surface 208 may be held tight by the application of thefastening mechanisms 224, reducing the gap between the actuator 100 andthe mounting surface 208 and thereby reducing harborage points.

FIGS. 3A-3E depict further examples of hub and base assemblies foraffixing a robotic gripper to a robotic arm without using externalfastening mechanisms like bolts or screws. These assemblies may be usedin conjunction with, or as an alternative to, the assemblies of FIGS.2A-2D.

FIGS. 3A-3C depict the “twist-to-lock” nature of the hub/base assembly.The assembly includes one or more actuators 100 mounted into an actuatorholder 304, which may be formed of any suitable material such as plasticor metal. An overmolded elastomer layer 302 holds the actuators 100 onthe actuator holder 304 and covers crevices, corners, and other featuresof the actuators 100 that could serve as harborage points. For example,as shown in FIG. 3E, the overmolded elastomer layer 302 may cover theproximal end of the actuator 100 up to the ridge on the most-proximalaccordion extension. A gripper base 306 includes an inflation fluidchamber 310 for distributing inflation fluid to the actuators 100. Thegripper base 306 may be affixed or may be affixable to a robotic arm.

The actuator holder 304 is provided with one or more grooves 312configured to mate with, and interlock with, corresponding extensions314 on the gripper base 306. As shown in FIGS. 3B and 3C, the gripperassembly including the actuators 100, the overmolded elastomer layer302, and the actuator holder 304 may be placed over the gripper base 306and twisted to mate the extensions 314 into the grooves 312. It shouldbe noted that the interlocking mechanism may be reversed (e.g., withgrooves 312 on the gripper base 306 and extensions 314 on the actuatorholder 304).

The use of an interlocking system allows for a screwless assembly,thereby removing potential harborage points. Moreover, thisconfiguration allows the actuator holder 304 (along with the actuators100 and the overmolded elastomer layer 302) to be easily removed fromthe base 306 so that the base 306 may be easily cleaned out-of-place(i.e., when the base 306 has been removed from the robotic assembly).

FIG. 3D shows a close up exterior view of the assembled gripper system.As shown in FIG. 3D, the interface 308 at which the gripper base 306mates to the actuator holder 304 includes smooth, curved surfaces. Thus,both the gripper base 306 and the actuator holder 304 do not requiresharp corners at the interface 308, which reduces harborage points andallows for simpler cleaning. Moreover, surfaces that may come intocontact with chemical or biological material may have a smoothness valueof at least 1 microinch, more preferably at least 16 microinches, andmore preferably at least 32 microinches.

In general, throughout the application, and particularly in the case ofinternal angles, the angle between two surfaces may be at least 135°. Bymaking these internal angles relatively open, it is easier to cleanthese internal surfaces (e.g., with a brush or other tool). Similarly,when a curve is used, such as in the case of the interface 308, theradius of the curve may be at least 1/32″, or more preferably ⅛″, ormore preferably ¼″, depending on the application.

FIG. 3E shows an internal view of the various components of the grippersystem. An inflation fluid chamber 310 is provided in the gripper base306 for supplying inflation fluid to the actuators 100. An inflationfluid supply line 212 extends through the actuator holder 304, throughthe overmolded elastomer 302, and into the void 204 of the actuator 100.Multiple inflation fluid supply lines 212 may be provided (e.g., one foreach actuator 100 in the gripper assembly). The inflation fluid supplyline 212 may be configured to mate with a corresponding interface on theinflation fluid chamber 310, or may simply extend to a large opening onthe inflation fluid chamber 310. Because most of the opening of thechamber 310 will be covered by the actuator holder 304, the only placefor inflation fluid to escape will be into the inflation fluid supplylines 212 and into the actuators 100.

As shown in FIG. 3E, the lower walls 316 inflation fluid chamber 310have a curved shape and relatively wide openings. Moreover, the internalsurfaces of the inflation fluid chamber 310 are relatively smooth (e.g.,having a smoothness value of 32 microinches or more. These featuresreduce harborage points, allows cleaning fluid to drain out of the baseafter cleaning, more readily allows access by cleaning tools such asbrushes, and provide for easier visual inspection to ensure that theinflation fluid chamber 310 has been sufficiently cleaned.

FIGS. 4A-4D depict a further example of a hub according to exemplaryembodiments.

FIGS. 4A and 4B depict a hub having an external fixturing mechanism 224.As shown in FIG. 4A, a number of actuators 100 are secured together toform a gripper. The actuators 100 are inserted into a plate 402, and theplate 402 is affixed to a robotic base 404 (e.g., a robotic arm oranother structure to be fixed to a robotic arm). The plate 402 issecured to the robotic base 404 using a fixturing mechanism 224 (e.g., ascrew or bolt), as shown in the closeup in FIG. 4B. The protrudingfixturing mechanism 224 provides a number of harborage points for thegripper system.

In contrast, FIG. 4C depicts a perspective view of a hub having aninternal fixturing mechanism. As can be seen in this example, the plate402 presents a flat surface with no external screws. As shown in thecross-sectional view of FIG. 4D, an internal fixturing mechanism 224 isrouted through an inflation fluid supply path 212, and secures the plate402 from the bottom.

Using the above-described hub assemblies (individually or in anycombination), harborage points can be reduced or eliminated from theinterconnections between the actuators/actuator holders and other partsof the system. Other harborage points may exist elsewhere, however. Forexample, inflation fluid may be supplied to a hub or other part of thesystem through an inflation fluid supply line such as a pneumaticfitting. FIGS. 5A-5H depict an example of a twist-lock inflation fluidsupply line for reducing harborage points, according to an exemplaryembodiment.

FIG. 5A provides a perspective view of a gripper including fouractuators 100 connected to an actuator holder 502. The actuator holder502 may be mounted to a robotic arm.

As shown in the close-up of FIG. 5B, the actuator holder 502 includes aport 504 for receiving a fitting 506 for an inflation fluid supply line.The port 504 is configured to interconnect with the fitting 506 througha twist interlock system. In this example, the port 504 includes one ormore fingers 508 that mate to one or more filleted slots 510 on thefitting 506. The filleted slots 510 may be relatively wide or thick toallow for easy cleaning (thus more easily receiving a brush or othercleaning device as compared, for example, to screw threads). Theinternal bend 509 in the fingers 508 may have a curved or teardropcross-sectional profile, with a curve radius of at least 1/32″, or morepreferably 1/16″, or more preferably ¼″, in order to grip the filletedslots 510 while also remaining relatively easy to clean (as e.g.,enabling easier access with a cleaning tools such as a brush).

One or more grooves 512 in the fitting 506, each groove corresponding toa finger 508, provide clearance allow the fitting 506 to be pushed ontothe port 504 between the fingers 508, as shown in FIG. 5C.

Once inserted onto the port 504, the fitting 506 may be twisted to lockthe fitting 506 into place, as shown in FIG. 5D. In an exemplaryembodiment, the fitting 506 may be twisted about 120° to allow forrelatively simple assembly, although other degrees of twist (e.g., 90°or 30°) are also possible. In order to accommodate this amount oftwisting, the grooves 510 may be shaped and configured to allow for a120° twist. Moreover, the grooves 510 may be shaped with an upward curveso that, as the fitting 506 is twisted, the fitting 506 undergoes lineardisplacement towards the hub 502, thus pressing the fitting 506 intoplace against the hub and creating a fluid-tight seal.

FIGS. 5E-5H depict the twisting action in more detail. FIG. 5E depictsan external view of an unlocked fitting 506 from the front, while FIG.5H depicts an internal cross-sectional view of the unlocked fitting 506from the side. Note that, in the unlocked configuration, a gap 514exists between the bottom of the fitting 506 and the hub 502.

FIG. 5G depicts an external view of a locked port 504 (after twistingthe port 504 to lock it in place) from the front, while FIG. 5H is aninternal view of the locked port 504 from the side. By comparing FIG. 5Fto FIG. 5H, it can be seen that twisting the port 504 results in anamount of linear displacement d which brings the bottom of the port 504into contact with the hub 502.

Alternatively or in addition, magnets may be used to secure an inflationfluid supply line to a hub. FIG. 6 depicts a magnetic attachment for aninflation fluid supply line, according to an exemplary embodiment. Inthis example, a hub 602 supports two actuators 100. The hub 602 isprovided with a first annular magnet 606 surrounding an inflation fluidsupply path 212. An inflation fluid supply line 610 for providinginflation fluid to the hub 602 includes a fitting 608 that incorporatesa second annular magnet 604. The first annular magnet 606 and the secondannular magnet 604 may have opposite polarities so that, when broughtinto close proximity with one another, the first annular magnet 606mates with the second annular magnet 604 and forms a fluid-tight seal.Because the magnets 604, 606 are annular, inflation fluid flows throughthe hole in the magnets 604, 606 and into the hub 602, from which it canbe distributed to the actuators 100.

Next, innovations in actuator design and application for handlingbiological or chemical materials is discussed.

Actuator Design and Application

FIGS. 7A-7B depict an example of an actuator having reduced harboragepoints, according to an exemplary embodiment. FIG. 7A depicts a firstactuator 700, in which the ridges 106 of adjacent accordion extensions104 are separated by relatively large distances r, and the troughs 108are relatively deep (represented by the distance t). Both the ridges 106and the troughs 108 have relatively sharp curves or sharp corners.Particularly in the case of the troughs 108, which have interior anglesinto which it may be difficult to place a brush or cleaning mechanism,these curves and corners create a number of harborage points 702.

FIG. 7B depicts a modified actuator 704. In this example, the ridges 106of adjacent accordion extensions are further apart (separated by arelatively larger distance r′), while the troughs 108 are more shallow(represented by the distance t′, which is less than t). The ridges 106and the troughs 108 have more rounded edges, with gentler curves.

As a result, edges on the actuator 704 are smoothed, reducing bacterialharborage points. Moreover, clearings on the actuator 704 are expanded,which makes it easier to clean the actuator 704 with a brush, pad,solution, etc. to remove bacteria and food debris from the actuator 704.

To further reduce harborage points, the accordion extensions 104 may becovered entirely so that the non-gripping side of the actuator presentsa smooth or flat surface. FIGS. 8A-8C depict an accordion cover for asoft actuator, according to an exemplary embodiment.

FIG. 8A depicts an actuator 100 having a plurality of accordionextensions 104. A most-proximal accordion extension includes a startingridge 802, and a most-distal accordion extension includes an endingridge 804.

To eliminate or reduce harborage points between or on the accordionextensions 104, the accordion extensions 104 may be covered with anaccordion cover 806, as shown in FIG. 8B. The accordion cover 806 may beformed of a highly extensible elastomer configured to readily flex whenthe actuator 100 is inflated with inflation fluid or subjected to avacuum. Thus, the accordion cover 806 does not hinder the expansion orcontraction of the actuator 100.

The accordion cover 806 may be removable, or may be integrated with theactuator 100. For example, the accordion cover 806 may be an elastomerthat fully encases the accordion extensions 104 and fills in the areasbetween the accordion extensions 104.

As shown in the internal cross-sectional view of FIG. 8C, the accordioncover 806 may extend from the starting ridge 802 to the ending ridge804. In other embodiments, the accordion cover 806 may extend beyond thestarting ridge 802 and/or the ending ridge 804. Alternatively or inaddition, the accordion cover 806 may cover some, but not all, of theaccordion extensions 104.

The gripping surface of the actuator 100 may also be supplemented. Forexample, FIG. 9 depicts an example of an overmolded soft gripping pad902, according to an exemplary embodiment. The soft gripping pad 902 isprovided on at least a portion of the gripping surface of the actuator100. The soft gripping pad 902 may be integral with the actuator 100, ormay be a separate part that is affixed to the actuator 100 (e.g., usingelastomeric bands), allowing the pad 902 to be removed for separatecleaning.

The soft gripping pad 902 may be formed of a soft elastomeric material(e.g., an elastomeric material that is relatively more flexible,pliable, or yielding to a force than the elastomeric material from whichthe actuator 100 is formed) and may allow the actuator 100 to manipulatedelicate objects, such as tomatoes, without bruising the objects'surface.

An interface 904 between the gripping pad 902 and the base 102 of theactuator 100 is curved to reduce or eliminate a potential harboragepoint.

In further embodiments, the gripping surface of the actuator 100 may beprovided with other types of texturing that are readily cleaned. Forexample, FIGS. 10A-10C depict cross-sectional side views of actuatorshaving inflatable texturing surfaces, according to exemplaryembodiments.

FIG. 10A depicts an actuator 100 in an uninflated state. The actuator100 includes a wall 202 surrounding a void 204 into which inflationfluid may be supplied. On the base 102 of the actuator, the thickness ofthe wall 202 varies between alternating thick-walled portions 1002 andthin-walled portions 1004. The thin-walled portions 1004 have athickness that is relatively smaller than the thick-walled portions1002.

In the uninflated state, the base 102 of the actuator 100 is flat. Thus,when not inflated, the actuator exhibits fewer or no harborage points onthe base 102 that forms the gripping surface, and can be readilycleaned.

However, when inflated (as shown in FIG. 10B), the inflation fluidenters the void 204 and presses against the external walls 202 of theactuator. Because the thin-walled portions 1004 are less rigid orresistant to inflation than the thick-walled portions 1002, thethin-walled portions 1004 may bow out, creating a textured base 102.Thus, the actuator 100 may more readily grip an object. When theinflation fluid is removed, the thin-walled portions 1004 return totheir flat configuration and the base 102 becomes smooth again, for easycleaning.

Note that FIG. 10B depicts the base 102 in a textured configuration(implying the presence of inflation fluid in the void 204), although theactuator 100 is in an unbent configuration. In real-world scenarios,applying inflation fluid would typically cause the actuator 100 to bend,as shown in FIG. 1A; the bending is not shown in FIG. 10B for ease ofunderstanding.

Instead of the thin-walled portions 1004 and the thick-walled portions1002, the base 102 may be formed of alternating materials of differenttypes that are more or less resistant to expansion upon inflation. Wheninflated, the portions of the base 102 with less resistant materialswill expand more than the portions of the base 102 with more resistantmaterials, creating a textured surface.

Moreover, a similar effect may be achieved by applying a vacuum insteadof inflation fluid. For example, the thin-walled portions 1004 may beconfigured to be in an extended configuration by default. Uponapplication of a vacuum, the thin-walled portions 1004 may bow inwards,creating a flat surface.

FIG. 10C depicts an alternate configuration in which the texturing ofthe base may be applied independently of inflation of the actuator 100.In this example, an internal wall 1006 separates the void 204 into twochambers. A first chamber 1008 exists in the area adjacent to the base102, while a second chamber 1010 fills the remainder of the actuator100. The two chambers 1008, 1010 may be inflated independently of oneanother. When the first chamber 1008 is filled, the thin-walled portions1004 bow outwards, creating a textured surface on the base 102. When thesecond chamber 1010 is filled, the actuator 100 bends according to itsinflation profile in order to grasp a target.

In addition to providing systems that reduce harborage points, it mayalso be useful when working with biological or chemical materials to usespecial purpose actuators well-suited to contexts in which thesematerials are often handled.

For example, FIGS. 11A-11D depict an exemplary tapered soft actuator1100. FIG. 11A depicts a perspective view of the tapered actuator 1100,while FIGS. 11B, 11C, and 11D depict side, front, and bottom views,respectively. As shown in these Figures, the actuator 1100 tapers bothin thickness (t) and in breadth (b) from the proximal end 112 to thedistal end 110.

It is noted that the tapered actuator 1100 need not necessarily taperuniformly across or along the actuator 1100. For example, differenteffects may be achieved by utilizing different relative degrees of taperalong the width, length, or wall thickness of the actuator, or bytapering the amplitude of respective accordions, resulting in analteration of lateral actuator stability, axial finger stability,gradient changes in expansion when actuated, or gradient changes incurvature response when actuated, respectively.

A tapered actuator 1100 is exceptionally stable in torsion, has a largesurface area for friction-dominated grasp, maintains small and dexterousfinger tips for manipulation of small items, and delivers relativelyhigher grasping force per the same pressure as compared to an actuatorhaving a homogeneous cross-section. This allows tapered actuators 1100to be deployed in tandem with each other, for example in a circular orrectangular pattern, for precision handling of a range of object sizesand weights. Moreover, tapered actuators 1100 are particularlywell-suited to manipulating wet, slippery, oddly/irregularly shaped, andcluttered food items (e.g., food items in a heap or in form fittingpackaging).

Moreover, a tapered actuator 1100 may be better able to navigatecluttered environments as compared to a non-tapered actuator (e.g.,bushels of unstructured fruit or produce).

For example, FIGS. 12A-12D depict an exemplary spherically envelopinggripper employing skewed actuators 1200. These leaf-shaped skewedactuators 1200 are well-suited to fully enclosing fragile objects. FIG.12A depicts a perspective view of a gripper employing four skewedactuators 1200, whereas FIGS. 12B, 12C, and 12D depict front, side, andbottom views of the a single actuator 1200, respectively.

As can be seen in FIG. 12D (bottom view), the skewed actuator 1200includes a plurality of skewed internal chambers 1202 for receivinginflation fluid. The skewed chambers 1202 have a teardrop or otherskewed shape that expands from a relatively narrow region r₁ to arelatively wider region r₂. The relatively narrow r₁ region may bedisposed close to the center of the skewed actuator 1200 (e.g., theportion of the internal chamber 1202 that is closest to the centerlineA-A, as shown in FIG. 12B), whereas the relatively wider region r₂ bedisposed towards the external edge of the skewed actuator 1200, awayfrom the centerline A-A.

The skewed actuators 1200 have a number of characteristics.

First, each skewed actuator 1200 has multiple degrees of freedom whenactuated. In other words, the skewed actuators 1200 bend about its majoraxis (e.g., around the central axis to curve in the circumferentialdirection as depicted in FIGS. 1A and 1B) as well as across its minoraxis (in the axial direction of FIGS. 1A and 1B).

Second, the skewed actuator 1200 has a relatively broad leaf-like shapewhich tends to form a completely enclosing sphere when matched withother tapered actuators 1200 in a circularly- or rectangularly-patternedlayout.

Third, the tapered design of the skewed actuator 1200 improves stabilityand increases grasping force. These properties make such an actuatorwell-suited to manipulating, for example, many types of roughly roundfruits and vegetables. Because the skewed actuator 1200 encompasses anobject (referred to herein as providing a “caging” grip), the skewedactuator 1200 may allow the skewed actuator 1200 to, for example, pickdelicate fruit from a tree (e.g., apples) or vine (e.g., tomatoes orgrapes). A task such as fruit picking may require a stronger grip than,for example, simply moving picked fruit from one location to another.Because a stronger grip is required, if the grip is focused in a fewlocations (e.g., at the fingertips of the actuators), then the fruit canbe bruised or damaged. By applying a caging grip, this force may bedistributed over a larger surface area, which improves the chances ofpicking the fruit without bruising it.

Objects may be fully encompassed or encapsulated by other methods aswell. For example, FIGS. 13A-13B depict webbing 1302 applied betweenactuators 100 in order to allow the actuators 100 to fully encapsulateobjects. The webbing 1302 may be formed of relatively extensibleelastomeric material to allow the webbing to expand while the actuators100 are in an open state (FIG. 13A), while maintaining a reasonableamount of tension when the actuators 100 are in a closed state (FIG.13B), so as to maintain the grasped object within the webbing 1302. Theuse of webbing 1302 allows for increased surface area contact between agripper and an object.

In some cases, an object to be grasped may be located deep within acontainer, such as a bin, where the object may be difficult to reach.FIGS. 14A-14B depict exemplary extend-and-grasp actuators suitable forthese and other applications.

FIG. 14A depicts an inflated extensible actuator 1400, while FIG. 14Bdepicts an uninflated extensible actuator 1400. The extensible actuator1400 includes a number of accordion extensions 104 divided into twosections. A full accordion section 1402 includes accordion extensions104 that extend around a full diameter of the extensible actuator 1400.A partial accordion section 1404 includes accordion extensions 104 thatextend only part way around the diameter of the extensible actuator1400. The full accordion section 1402 may include accordion extensions104 at a higher frequency or rate than the partial accordion section1404.

As a result, when the extensible actuator 1400 is inflated, at arelatively low inflation pressure the full accordion section 1402 beginsto extend (under a relatively small amount of force). This causes theextensible actuator 1400 to extend linearly, with a relatively smalldegree of curvature at the distal end, which allows the extensibleactuator 1400 to (for example) reach into a bin or container that mightotherwise be blocked by the actuator's hub assembly 1406. At relativelyhigh inflation pressure, the partial accordion section 1404 exhibitsincreasing degrees of curvature, allowing the extended actuator to graspan object.

In further embodiments, an actuator may employ a special geometry inorder to better grasp particular targets. For example, FIG. 15A-15Ddepict an actuator incorporating a hook, according to an exemplaryembodiment.

As shown in FIG. 15A, the hooked actuator 1500 includes a curvedprotrusion 1502 at its distal end in the shape of a hook. Accordingly,when the hooked actuator 1500 is inflated in order to grasp an object(FIGS. 15B, 15C, and 15D, showing varying degrees of inflationpressure), the curved protrusion 1502 of the hooked actuator 1500extends underneath the object to be grasped (FIG. 15C), subsequentlypulling the object inward (FIG. 15D). This allows for greater contactwith the gripping surface of the hooked actuator 1500, and improves thestability of the object while it is being moved or manipulated.

Regardless of the type of actuator used, it may be helpful in somescenarios to increase the opening between actuators prior to grasping atarget. For example, when grasping a large object, a relatively largeopening angle may be called for. When grasping a small object, arelatively small opening angle may be called for.

To achieve different degrees of opening, vacuum may be applied to theactuator (e.g., instead of filling the actuator with an inflation fluid,ambient fluid in the actuator may be removed from the actuator). Forinstance, FIGS. 16A-16B depict examples of different degrees of vacuumapplied to actuators 100 to modify the actuators' opening profile. FIG.16A depicts a relatively large opening angle achieved by applying arelatively large amount of vacuum to the actuators 100. FIG. 16B depictsa relatively small opening angle achieved by applying a relativelysmaller (or no) amount of vacuum.

In some embodiments, a robotic system is configured to provide aprecise, predetermined amount of vacuum to one or more actuators 100.The predetermined amount may be selected in an amount that accommodatesthe environment in which the actuator 100 is intended to operate and thesize or configuration of the object that the actuator 100 is intended tograsp. For example, if too little vacuum is applied, the actuator 100will not open sufficiently to grasp the target. On the other hand, iftoo much vacuum is applied, the actuator 100 will open more widely thanis necessary, which may cause the actuator 100 to collide with thecontainer holding the target object and/or other objects near the targetobject. This is especially true in cluttered environments. By providinga predetermined amount of vacuum, the actuator 100 can be opened enoughto allow the target object to be grasped while still providingsufficient space between the actuator and adjacent objects orcontainers.

Robotic System Covering

In a further embodiment, the system may be made easier to clean byapplying a food-safe or medically-safe wrapping around some or all of arobotic system. For example, FIGS. 17A-17C depict an exemplarydisposable wrapping for a robotic system 1700.

As shown in FIG. 17A, the robotic system 1700 includes a robotic arm1702 to which a hub 1704 is mounted. Actuators 100 are connected to thehub 1704. A disposable wrapping 1706, which is sized and shaped tocorrespond to the robotic system 1700, is provided around the roboticsystem 1700.

The disposable wrapping 1706 is sized and shaped to be relatively loosewhen the actuators 100 are in an uninflated state (FIG. 17B) andrelatively tighter (without risking breakage of the disposable wrapping1706) when the actuators 100 are in an inflated state (FIG. 17C). Forexample, the size and shape of the bag may be selected so as to providea predetermined amount of slack when the actuators 100 are uninflated.When the actuators 100 are inflated, the slack is reduced and theactuators 100 may grip a target object. Alternatively or in addition,the disposable wrapping 1706 may be formed of elastic materials in orderto allow the disposable wrapping 1706 to compensate for inflation of theactuators 100.

It is noted that the wrapping 1706 need not necessarily be disposable.In some embodiments, the wrapping 1706 may be capable of removal forcleaning, and may be re-used once cleaned.

Using the above-described embodiments, individually or in combinationwith each other, biological and chemical materials may be more readilyhandled by robotic systems. The described embodiments reducebiological/chemical/bacterial harborage points, allow for easy cleaning,and improve the grasping and reaching capabilities of grippers, amongother advantages.

1. A soft actuator comprising: an elastomeric body that extends from aproximal end to a distal end, the elastomeric body: surrounding a voidconfigured to receive an inflation fluid, and comprising a plurality ofaccordion extensions, wherein the elastomeric body is configured to curlin response to pressurization upon receiving the inflation fluid; and agripping surface provided on the elastomeric body, the gripping surfaceconfigured to transition between a first state in which the grippingsurface is textured and a second state in which the gripping surface issubstantially untextured in response to a pressurization event.
 2. Thesoft actuator of claim 1, wherein the gripping surface is providedopposite the accordion extensions.
 3. The soft actuator of claim 1,wherein the gripping surface comprises a plurality of inflatabletexturing surfaces.
 4. The soft actuator of claim 3, wherein thepressurization event comprises receiving inflation fluid in at least aportion of the void to cause the inflatable texturing surfaces toextend.
 5. The soft actuator of claim 1, wherein the gripping surfacecomprises a plurality of retractable texturing surfaces.
 6. The softactuator of claim 5, wherein the pressurization event comprises applyinga vacuum to at least a portion of the void to cause the retractabletexturing surfaces to retract.
 7. The soft actuator of claim 1, whereinthe gripping surface comprises a wall having alternating relativelythick portions and relatively thin portions.
 8. The soft actuator ofclaim 1, wherein the gripping surface comprises a wall havingalternating relatively more expansion-resistant portions and relativelyless expansion-resistant portions.
 9. The soft actuator of claim 1,wherein the relatively more expansion-resistant portions are made up ofa different material than the relatively less expansion-resistantportions.
 10. The soft actuator of claim 1, wherein the void is dividedinto a first chamber and a second chamber by an internal wall.
 11. Thesoft actuator of claim 10, wherein the first chamber is providedadjacent to the gripping surface, and the pressurization eventpressurizes or depressurizes the first chamber without pressurizing ordepressurizing the second chamber.
 12. The soft actuator of claim 10,wherein the second chamber is provided adjacent to the accordionextensions, and further comprising pressurizing or depressurizing thesecond chamber without pressurizing or depressurizing the first chamber.13. A method comprising: accessing a soft actuator according to claim 1;effecting the pressurization event to transition the gripping surface tothe first state; and applying the soft actuator to grasp a targetobject.
 14. The method of claim 13, further comprising: effecting asecond pressurization event to transition the gripping surface to thesecond state; and cleaning the gripping surface.